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- Chen, Weimin, et al.
(author)
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P-N defect in GaNP studied by optically detected magnetic resonance
- 2003
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In: Proceedings of the 22nd International Conference on Defects in Semiconductors. - : Elsevier BV. ; , s. 399-402
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Conference paper (peer-reviewed)abstract
- We provide experimental evidence for an intrinsic defect in GaNP from optically detected magnetic resonance (ODMR). This defect is identified as a P-N complex, exhibiting hyperfine structure due to interactions with a nuclear spin I=12 of one P atom and also a nuclear spin I=1 due to one N atom. The introduction of the defect is assisted by the incorporation of N within the studied N composition range of up to 3.1%, under non-equilibrium growth conditions during gas-source molecular beam epitaxy. The corresponding ODMR spectrum was found to be isotropic, suggesting an A1 symmetry of the defect state. The localization of the electron wave function at the P-N defect in GaNP is found to be even stronger than that for the isolated PGa antisite in its parent binary compound GaP. © 2003 Elsevier B.V. All rights reserved.
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| 5. |
- Dagnelund, Daniel, 1980-, et al.
(author)
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Optically detected cyclotron resonance studies of InGaNAs/GaAs structures
- 2007
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In: Physics of semiconductors : 28th International Conference on the Physics of Semiconductors, ICPS 2006, Vienna, Austria, 24-28 July 2006. - : American Institute of Physics (AIP). - 9780735403970 ; , s. 383-384
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Conference paper (other academic/artistic)abstract
- We report on our recent results from a systematic study of layered structures containing an InGaNAs/GaAs quantum well (QW), by the optically detected cyclotron resonance (ODCR) technique. By monitoring photoluminescence (PL) emissions from various layers the predominant ODCR peak is shown to be related to carriers with a 2D character and an effective mass of 0.51 m∗e. The responsible carriers are ascribed to be electrons in GaAs/AlAs superlattices (SL) that are employed in the laser structures to prevent carrier leak by sandwiching the InGaNAs/GaAs QW. This conclusion is based on the following observations: (a) the ODCR peak is only observed in the structures containing the SL; (b) the effective mass value determined by the ODCR peak is independent of In and N compositions; (c) the same ODCR peak is also observed by monitoring PL from the SL. Unfortunately no ODCR signal related to InGaNAs was observed
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| 6. |
- Dagnelund, Daniel, 1980-, et al.
(author)
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Optically detected cyclotron resonance studies of InxGa1-xNyAs1-y/GaAs quantum wells sandwiched between type-II AlAs/GaAs superlattices.
- 2007
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In: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 101, s. 073705-
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Journal article (peer-reviewed)abstract
- We report on our results from a systematic study of layered structures containing an InGaNAs/GaAs single quantum well (SQW) enclosed between staggered type II AlAs/GaAs superlattices (SL), by the photoluminescence (PL) and optically detected cyclotron resonance (ODCR) techniques. Besides the ODCR signal known to originate from electrons in GaAs, the predominant ODCR peak is shown to be related to carriers with a two-dimensional character and a cyclotron resonance effective mass of m*[approximate](0.51-0.56)m0. The responsible carriers are ascribed to electrons on the ellipsoidal equienergy surface at the AlAs X point of the Brillouin zone within the SL, based on results from angular and spectral dependences of the ODCR signal. No ODCR signal related to the InGaNAs SQW was detected, presumably due to low carrier mobility despite the high optical quality. Multiple absorption of photons with energy below the band gap energy of the SL and the GaAs barriers was observed, which bears implication on the efficiency of light-emitting devices based on these structures.
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| 7. |
- Dagnelund, Daniel, et al.
(author)
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Phosphorus-related interfacial defect complex at a GaP/GaNP heterojunction
- 2010
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Conference paper (other academic/artistic)abstract
- For full exploration of dilute nitrides in device applications, a better understanding and control of defects located at interfaces involving e.g. Ga(In)NP are required. In this work we report on the first identification of a point defect situated at an interface between two semiconductors: GaNP and GaP. The defect is concluded to be a complex involving a P antisite or a P interstitial in its core, partnered with a neighboring impurity/defect aligned along a <111> direction, from detailed angular dependence studies of the optically detected magnetic resonance (ODMR) spectra at both X- and Q-band microwave frequencies. The principal g and A values, g┴=2.013, g║=2.002, A┴=130x10-4 cm-1 and A║=330x10-4 cm-1, are obtained from a spin Hamiltonian analysis. The interface nature of the defect is clearly evident from the absence of the ODMR lines originating from two out of four equivalent <111> orientations. Defect formation is shown to be facilitated by severe nitrogen ion bombardment under non-equilibrium growth conditions during solid-source molecular beam epitaxy and the defect is thermally stable upon post-growth thermal annealing.
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| 8. |
- Dagnelund, Daniel, 1980-, et al.
(author)
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Spin resonance spectroscopy of grown-in defects in Ga(In)NP alloys
- 2008
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In: 7th International Conference on Physics of Light-Matter Coupling in Nanostructures, 2007. - : Elsevier Ltd.. ; , s. 620-625
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Conference paper (peer-reviewed)abstract
- We employ the optically detected magnetic resonance (ODMR) technique to study and identify important grown-in defects in Ga(In)NP grown by molecular-beam epitaxy (MBE). Several types of defects were revealed from ODMR studies. The dominant defects were found to be related to Ga interstitials, evident form their characteristic hyperfine interaction arising from the spin interaction between the electron and the Ga nucleus. Some other as yet unidentified intrinsic defects were also found to be commonly present in the alloys. The effects of growth conditions (ion bombardment, N2 gas flow, etc.) and post-growth rapid thermal annealing on the formation of these defects were studied in detail, shedding light on the formation mechanism of defects.
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| 9. |
- Izadifard, Morteza, et al.
(author)
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Band alignment in GaInNP/GaAs heterostructures grown by gas-source molecular-beam epitaxy
- 2005
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In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 86:26, s. 261904-
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Journal article (peer-reviewed)abstract
- Low-temperature photoluminescence (PL), PL excitation, and optically detected cyclotron resonance measurements are employed to determine band alignment in GaInNP/GaAs heterostructures grown by gas-source molecular-beam epitaxy. The type II band alignment at the Ga0.46In0.54NxP1−x/GaAs interface is concluded for the alloys with x ≥ 0.5% based on (i) highly efficient PL upconversion observed in the N containing samples and (ii) appearance of a near-infrared PL emission attributed to the spatially indirect type II transitions. Compositional dependence of the conduction band offset at the Ga1−yInyNxP1−x/GaAs interface is also estimated.
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| 10. |
- Izadifard, Morteza, 1965-, et al.
(author)
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Evaluation of optical quality and defect properties of GaNxP1−x alloys lattice matched to Si
- 2004
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In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 85, s. 6347-
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Journal article (peer-reviewed)abstract
- By using a variety of optical characterization techniques, including cathodoluminescence, temperature-dependent cw- and time-resolved photoluminescence (PL), and PL excitation spectroscopies, high optical quality of the GaN0.018P0.982 epilayers lattice matched to Si substrates is demonstrated and is shown to be comparable to that of the “state-of-the-art” GaNP alloys grown on GaP substrates. The growth of GaNP on Si is, however, found to facilitate the formation of several point defects, including complexes involving Ga interstitial atoms (Gai).
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